Preparation of hydroxypolyamides

ABSTRACT

Hydroxypolyamides can be obtained in a simple and economical way in a chloride-free manner when 
     (a) aromatic amino hydroxy carboxylic acids or 
     (b) aromatic diaminodihydroxy compounds and aromatic dicarboxylic acids or 
     (c) aromatic diaminodihydroxy compounds, aromatic dicarboxylic acids and aromatic amino hydroxy carboxylic acids are converted in the presence of 1-ethoxycarbonyl-2-ethoxy-1.2-dihydroquinoline, 1.1&#39;-carbonyldioxy-di-1.2.3-benzotriazole or dicyclohexyl carbodiimide/1-hydroxy-1.2.3-benzotriazole.

This is a division of application Ser. No. 07/501,169 filed Mar. 29,1990.

FIELD OF THE INVENTION

The invention concerns a method for preparing hydroxypolyamides.

BACKGROUND OF THE INVENTION

Hydroxypolyamides serve as soluble oligomeric and/or polymericpolybenzoxazole precursors in thermoresistant photoresists for producingheat resistant relief structures; i.e., for the economical directstructuring of organic insulating layers. In addition to a high thermalload capacity (>450° C.) and very good electrial characteristic values,a very high purity is also required of insulating materials which remainin microelectronic components. Thus, the concentration of e.g. chlorideions should lie distinctly below 3 ppm. This is because chloride ionsimpair the electrical properties of the components and they cannegatively influence the long-term stability of the components throughcorrosion processes.

Soluble, and therefore having good workability, polybenzoxazoleprecursors in the form of hydroxypolyamides which are converted intohigh-temperature-resistant polybenzoxazoles by means of a temperaturetreatment, are known from e.g. EP-PS 0 023 662, EP-OS 0 291 779 andDE-OS 37 16 629. These polybenzoxazole precursors are prepared startingfrom aromatic diaminodihydroxy compounds and aromatic dicarboxylic acidchlorides. In order to reach the low degree of ionic impurities requiredin microelectronic engineering, it is usually necessary to performextensive purifying operations by means of ion exchangers. Suchpurifying operations involve labor- and cost-intensive processes.Another drawback of such purifying operations is that organicimpurities, e.g. amines stemming from anion exchangers, can get into theresinous matter and negatively influence the properties of the resinousmatter.

A chloride-free synthesis of polybenzoxazole precursors is known fromEP-OS 0 158 726. In this connection, diaminodihydroxy compounds arecaused to react with dicarboxylic acids in the presence of acarbodiimide. During this conversion, though, carbamide residues, whichremain due to a rearrangement reaction on the resin, cause difficulties.Namely, these residues impair the thermal resistance of thepolybenzoxazole precursors and the constitution of layers made out ofthem.

Accordingly, it is an object of the invention to specify a simple andeconomical method for preparing hydroxypolyamides in a chloride-freemanner.

SUMMARY OF THE INVENTION

The invention provides a method for preparing hydroxypolyamides wherein

(a) aromatic amino hydroxy carboxylic acids or

(b) aromatic diaminodihydroxy compounds and aromatic dicarboxylic acidsor

(c) aromatic diaminodihydroxy compounds, aromatic dicarboxylic acids andaromatic amino hydroxy carboxylic acids are converted in the presence of1-ethoxycarbonyl-2-ethoxy-1.2-dihydroquinoline,1.1'-carbonyldioxy-di-1.2.3-benzotriazole or dicyclohexylcarbodiimide/1-hydroxy-1.2.3-benzotriazole into compounds of thefollowing structure: ##STR1## where R, R*, R₁, R*₁ and R₂ are aromaticgroups and regarding n₁, n₂ and n₃, the following holds:

n₁ and n₂ =1 to 100, n₃ =0 or

n₂ =1 to 100, n₁ and n₃ =0 or

n₁, n₂ and n₃ =1 to 100 (with R≠R* and/or R₁ ≠R*₁) or

n₁ and n₃ =1 to 100, n₂ =0 (with R≠R* and/or R₁ ≠R*₁).

DETAILED DESCRIPTION OF THE INVENTION

The method according to the invention, in which special reagents areused for the condensation reaction between amino groups and carboxylgroups, supplies the desired polybenzoxazole precursors in good yield.This is shown by spectroscopic analyses such as IR [infrared] and NMR[nuclear magnetic resonance] measurements. This fact, however, was verysurprising for the following reason. In the organic synthesis and inpeptide chemistry, a series of reagents have been developed which permitspecial esterifications, e.g. of sterically hindered alcohols, and thelinking of peptide bonds, among them1-ethoxycarbonyl-2-ethoxy-1.2-dihydroquinoline and1.1'-carbonyldioxy-di-1.2.3-benzotriazole. As such spectroscopicanalyses have shown, these reagents do not, however, result in thedesired polymer precursors with the exception of those which are used inthe method according to the invention.

In the method according to the invention for preparing hydroxypolyamidesthe preparation can start with the appropriate carboxylic acids in placeof acid chlorides. Therefore, purification steps, in particular thoseusing ion exchangers, can be dispensed with so that a simple andeconomical synthesis is made possible.

In the method according to the invention, the reaction between the aminofunctional hydroxy compounds and the carboxylic acids is advantageouslycarried out in an organic solvent. Preferably, N-methylpyrrolidoneand/or pyridine is used as a solvent. The conversion itselfadvantageously takes place at temperatures from room temperature toapproximately 60° C.

The hydroxypolyamides prepared according to the method of the inventionpreferably possess aromatic groups of the following structure. R and R*can have the following significance: ##STR2## R₁ and R*₁ can have thefollowing significance, where H-atoms can also be substituted by Cl orBr: ##STR3## R₂ can have the following significance: ##STR4##

Thereby, T₁ to T₇ signify H or alkyl, m=0 or 1, and X signifies:##STR5##

Thereby the following holds:

Z=alkyl with 1 to 10 carbon atoms or aryl, and

r=2 to 18.

The invention shall be more closely explained in light of theexemplified embodiments.

EXAMPLE 1 Conversion of Isophthalic Acid using 3.3'-dihydroxy benzidine

8.32 parts by weight 1-ethoxycarbonyl-2-ethoxy-1.2-dihydroquinoline and2.79 parts by weight isophthalic acid, dissolved in 15 parts by weightN-methylpyrrolidone, are mixed in a 250 ml three neck flask providedwith an agitator, a dropping funnel and a drying tube for 75 minutes atroom temperature under an argon atmosphere. Next, a solution of 3.64parts by weight 3.3'-dihydroxy benzidine in 30 parts by weightN-methylpyrrolidone is added drop by drop and is subsequently mixed for6 hours at room temperature; then the solution is left to stand foranother 12 hours at room temperature. To isolate the resin, the reactionmixture is poured into 500 parts by weight methanol; then it is washedrepeatedly with the precipitating agent and is subsequently dried invacuum (at a pressure of approx. 270 mbar) at room temperature overCaCl₂ and NaOH; yield: 3.6 parts by weight (62% of theory). Theviscosity number amounts to 12.5 ml/g (1% solution inN-methylpyrrolidone at 23° C.).

EXAMPLE 2 Conversion of Isophthalic Acid using 3.3'-dihydroxy benzidineand 3.3'-diamino-4.4'-dihydroxydiphenyl-1.1.1.3.3.3-hexafluoro propane

50 parts by weight 1-ethoxycarbonyl-2-ethoxy-1.2-dihydroquinoline and16.8 parts by weight isophthalic acid, dissolved in 90 parts by weightN-methylpyrrolidone, are mixed for 45 minutes at room temperature underan argon atmosphere in a 1 1-three neck flask provided with an agitator,a reflux condensor, a dropping funnel and a drying tube. Next, this isheated to 50° C. and a solution of 10.94 parts by weight 3.3'-dihydroxybenzidine and 17.48 parts by weight3.3'-diamino-4.4'-dihydroxydiphenyl-1.1.1.3.3.3-hexafluoropropane in 150parts by weight N-methylpyrrolidone is added drop by drop. Subsequently,the solution is mixed for 5 hours at 50° C. and then is left to standfor another 12 hours at room temperature. The resin is isolated byprecipitation in 4000 parts by weight of a mixture of water and methanol(ratio 2:1) and subsequent suctioning off; then [it] is washedrepeatedly with water and is subsequently dried in vacuum (at a pressureof approx. 270 mbar) at room temperature over NaOH; yield: 26.6 parts byweight (63% of theory). The viscosity number amounts to 8.7 ml/g (1%solution in N-methylpyrrolidone at 23° C.).

EXAMPLE 3 Conversion of Isophthalic Acid Using 3.3'-dihydroxy benzidine

10.06 parts by weight 1.1'-carbonyldioxy-di-1.2.3-benzotriazole, 2.65parts by weight pyridine and 2.82 parts by weight isophthalic acid in 15parts by weight N-methylpyrrolidone are introduced under an argonatomosphere into a 250 ml three neck flask provided with an agitator, areflux condensor, a dropping funnel and a drying tube. A CO₂ developmentimmediately commences, which ends after approximately 5 minutes. Themixture is then mixed for 20 minutes at room temperature, issubsequently heated to 60° C., and a solution of 3.68 parts by weight3.3'-dihydroxy benzidine in 25 parts by weight N-methylpyrrolidone isadded drop by drop. Then the solution is mixed for 4 hours at 60° C. andis subsequently left to stand for another 12 hours at room temperature.The resin is precipitated in 1100 parts by weight methanol, theprecipate is suctioned off, washed repeatedly with methanol and is driedover NaOH at room temperature; yield: 4.5 parts by weight (77 % oftheory). The viscosity number amounts to 23.7 ml/g (1% solution inN-Methylpyrrolidone at 23° C.).

EXAMPLE 4 Conversion of Isophthalic Acid Using 3.3'-dihydroxy benzidine

5.67 parts by weight dicyclohexyl carbodiimide together with 5.4 partsby weight 1-hydroxy-1.2.3-benzotriazole are dissolved in 30 parts byweight N-methylpyrrolidone. A solution of 2.08 parts by weightisophthalic acid in 30 parts by weight N-methylpyrrolidone is added dropby drop to this mixture while being stirred, and is subsequently mixedfor 30 minutes. Then 2.7 parts by weight 3.3'-dihydroxy benzidine isadded drop by drop while being stirred; is subsequently mixed for 2hours and the precipitated dicyclohexyl-carbamide is filtered off fromthe reaction solution. The filtrate is added by drops into 600 parts byweight ice water while being stirred; the precipitated solid issuctioned off, washed repeatedly with water and is subsequently dried inthe vacuum-drying oven (at a pressure of approx. 270 mbar) over NaOH;yield: 4.3 parts by weight (90% of theory). The viscosity number amountsto 13.27 ml/g (1% solution in N-methylpyrrolidone at 23° C.).

What is claimed is:
 1. A method for preparing hydroxypolyamides havingthe following structure: ##STR6## where R, R*, R₁, R*₁ and R₂ arearomatic groups and where: n₁ and n₂ =1 to 100, n₃ =0 orn₂ =1 to 100, n₁and n₃ =0 or n₁, n₂ and n₃ =1 to 100, where at least one of thefollowing holds: R is other than R*, and R₁ is other than R*₁, or n₁ andn₃ =1 to 100, n₂ =0, where at least one of the following holds: R isother than R*, and R₁ is other than R*₁, comprising the step of reactingone of:(a) at least one aromatic amino hydroxy carboxylic acid, or (b)at least one aromatic diaminodihydroxy compound, at least one aromaticdicarboxylic acid and at least one aromatic amino hydroxy carboxylicacid, in the presence of 1-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline,1,1'-carbonyldioxy-di-1,2,3-benzotriazole or dicyclohexylcarbodiimide/1-hydroxy-1,2,3-benzotriazole.
 2. The method according toclaim 1 wherein the reaction occurs in an organic solvent.
 3. The methodaccording to claim 2 wherein the solvent is at least one ofN-methylpyrrolidone and pyridine.
 4. The method according to claim 1wherein the temperature during the reaction is set at room temperatureto approximately 60° C.
 5. The method according to claim 3 wherein thetemperature during the reaction is set at room temperature toapproximately 60° C.
 6. The method according to claim 3 wherein thetemperature during the reaction is set at room temperature toapproximately 60° C.